Removable drilling bit



June 7, 1949. c. c. KoELN 2,472,710

' REMovABLE DRILLING BIT Fild May 5, 1944 Patented June 7, 1949 UNITED STAE FATENT OFFICE 18 Claims. l

This invention relates to drilling apparatus, and more particularly to a removable drilling bit construction, said bit which embodies the invention being an improvement in the drilling bit covered by my Patent No. 2,337,720, issued December 28, 1943.

One of the objects of my invention is to produce an improved drilling bit which can be removed from the bottom of a hole being drilled without the necessity of removing the drilling shaft, said bit being so constructed that the movable cutters thereof are pivotally mounted.

Another object of my invention is to so construct a removable drilling bit embodying movable cutters as to provide means for properly supporting said cutter when in its operative position.

Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing in which:

Figure l is a longitudinal sectional View of my improved drilling bit showing itin operative position on the end of a drilling shaft;

Figure 2 is a bottom view of the drilling bit shown in Figure 1;

Figure 3 is a sectional view taken on the line 3 3 of Figure 1;

Figure 4 is another bottom View showing the relation between the bit and arbor port of the shaft prior to turning of the bit to its operative position; and

Figure 5 is a perspective view of one of the pivoted cutters.

Referring to the drawing in detail, numeral I indicates the drilling bit body, the peripheral surface of which has an irregular contour as shown in Figures 2 and 4. This body is provided with a central bore 2 which permits it to be slid over the usual hollow drilling shaft (not shown) oi the drilling apparatus. The lower end of this drilling shaft has secured to its end by threads a specially constructed short partially hollow shaft or arbor 3 forming part of the means for removably attaching the drilling bit body. The shaft 3 is provided with stepped enlargements Al and 5 adjacent its lower end. The upper and smaller enlargement 1I has a portion of its surface cut away to form right angle slots ii. The upper ends of these slots have flared open ends with the side wall portions of adjacent slots converging to form apexes 'I. The bore 2 is stepped to receive the enlargements 4 and 5 and its upper end 8 is of such diameter as to receive the portion of shaft 3 above the enlarged portion 4. The stepped arrangement of the bore 2 provides a 2 shoulder 9 which is adapted to engage the apexes I at the top of the enlarged portion on the shaft and a shoulder I0 which is adapted to engage the shoulder II at the top of the enlarged portion 5. The angular slots 6 have cooperating therewith the inner ends of pins I2 carried by the body portion. These pins, together with the an-v guiar slots, form a bayonet type of joint preventing any relative axial movement between the body of the bit and shaft 3 when the pins are positioned in the lateral legs of the slots. These pins also provide a driving connection between the short shaft 3 and the body of the bit so that the bit can turn with the shaft when the shaft rotates in the direction indicated by the arrow. The shoulders 9 and I l support the bit body.

The lower end of the body of the drilling bit is provided with alternate short and long radially positioned slots I3 and I4 extending in a longitudinal direction. In the short slots I3 which extend to the bore are positioned cutters l5 in the form of blades which are held in the slots by screws I6. The outer edges of these cutters eX- tend slightly beyond the periphery of the body member and provide a cutting edge for forming the wall of the hole, whereas the bottom edges of the cutters I5 which extend only to the bore of the body provide the cutting means for cutting away the earth substance at the bottom of the hole adjacent the side wall thereof.

In each of the long slots I4 there is positioned a cutter I'I in the form of an elongated blade, said cutter being pivotally mounted in the slot at its upper end by a pin I8, thus permitting the lower part of the cutter to swing back and forth on the pin axis. Each blade Il is of such width that when it is hanging in a generally vertical position it will be totally within the slot Iii and thus not interfere with the sliding movement of the bit body on the drilling shaft. Each blade il' is of special shape, being provided with a cutting` edge I9 at its lower end which is angularly related to the outer longitudinal edge of the blade. Also on the lower end of the blade is an edge 2t which is substantially at right angles to the cutting edge I9 and angularly related to the inner longitudinal edge. The upper end of each cutter has a projection 2i which is arranged for cooperation with the shoulder II at the lower end of the shaft t between the enlargements 4 and 5. This projection is arranged to extend into the portion of the bore which receives the enlargement 5 when saidcutter is hanging in its vertical position. in place of the cutting edge on the lower end of the v cutter,.there may be employed rotary cutting 3 elements similar to those shown in Figure of my Patent No. 2,337,720.

By pivoting the blade l1 on the bit body and constructing it as shown said cutter can be swung inwardly into the bore so as to assume a position where the edge I9 will be at substantially right angles to the axis of the shaft, and thereby be employed to cut the central part of the bottom of the hole being drilled. The projection 2l on the upper end of the cutter insures that the cutter will be swung inwardly to its proper operative position, as shown in Figure 1. When the bit body is lowered and reaches the end ofthel shaft 3, the extension 2l will be engaged by the shoulder and the cutter I1 will be swunginwardly,

The enlarged portion 5 at theextreme end of the shaft 3 is cut away to provide recesses 22 for receiving the blades i1 when they are swung inwardly to their operative position. These recessses are ofsuch widthandshape as to permit the blades to have the necessary relative movement Awith respectto the shaft, so that the bodymembercan be rotated to bring about its attachment by means of thebayonet type connecting means. When the bitbody is attached to the shaft, the wall 23 ofeach slot ywill b'ecome positioned so asfto be abutment with the rear surfaceof the c iitter I'Lvvnichv is received in the slot,i thus providing a backing means `on the shaft for the portion of the blade which extends into the bore 4of the bit body. This backing means or abllmentwill prevent cutting forces acting on the cutter from being effective to twist or bendthe lower part of lthe cutterrelative to the pivotally mounted part'. The enlargerrient 5 is also provided passages 24 so that the hollow portion of the drilling shaft and the shaft 3 can communicate with the bottom o'f the hole being drilled, and Athus" permit fluid which is forced dowrithrou'gh the drilling s haftto enter the bottom of the holeand aidin carrying away the cuttings from the drilling bit, as is well known in practice.

In order thaththe Adrilling.bit may b'e lowered to the end of the drilling shaft for attachment j thereto and removed to permit another drilling bit to be substituted thereforwithoiitthe necessity of removingthe drilling shaft from the hole, there is provided a suitable retrieving ring shown in Figurel. This ringconipri'ses an 'annular element carrying pivoted hooks 26. These hooks are 'adaptedto cooperate with an annular ledge 2 1 provided in the upper end of the bit body.A l`Each hook is' controlled by two cords or -cables 28 and 29, which also provide means for raising the bit from the bottom of thewell and also lowering it into the bottom of the well. When the bit is to be removed, the retrievingring is ylowered from t he top` of the well to where itis at the top of the body of the bit. The hooks canthen be engaged with the ledge 21 by pulling on thecords 29. Any other suitable retrieving tool can be employed in place of the o ne shown.

When the drilling bit is 4in operative position on the drilling shaft, it isas shown in Figures 1 2 and 3. Underthese conditions, the pinslz will be in the lateral legs o f the slots where they will be maintained since thedrilling shaft,will be rotated in the ldirection. of the arrows of Figu res 1 and 2. The pivoted Cutters II will bein positions where they extend intothe bore of the bit body being received in therecesses 2 2 of the enlargedportion 5 on thelowerend of the shaft, The back side of the blades will be abutting the walls 23. As the drilling shaft is rotated, the xed cutters I5 will cut the outer portion of the bottom of the hole and the cutters l1 will cut the central portion of the bottom of the hole.

When it is desired to remove the drilling bit, the drilling shaft may be raised a few feet in order to get the bit off the bottom of the hole and to be clear of any sediment which settles in the bottom of the hole if the hole has not been allowed to be cleaned out by the circulation of uid. The retrieving ring is dropped down '0 0k the drilling bit and its hooks connected to the ledge 2'l. The drilling shaft 3 is now given a slight reverse rotation which will result in the pins 1 2 b eing moved to the axial portions of the slots 6. The pivoted cutters will now be in the positions shown in Figure 4, that is, at the sides of the recesses opposite the walls 23. The bit is now free for sliding movement up the drilling shaft which is accomplished by merely pulling on the proper cables.' As the bitmoves upwardly, the ldwer end o'f the shaft V3 will push the pivoted cutte'rsl'l outwardly so that they will assume a vertical hanging position totally within the slots I4,- thus not interfering with tiie free movement of the bit up the shaft.

When a newb'it is lowered for attachment to the shaft section or arbor 3 at the lower end of the driiiing shaft, the cuttersi1 wiii be hanging in their vertical positions as he bit approaches its lowermost permissibleposition on the shaft, the extension 2| on the cutters willengage with the shoulder I I on theshaft 3 and thecutters l1 will be swung inwardlyto their operative positions', positions which will be present when the shoulder |0 e 1 ga'ge's the shoulderil and the shoulder 9 engages tl io apexe's 1, these apexes also functioning toguido thepiris l2 into the siot t. The cutters i1 now have positions iii the slots 2 2 as shown in Figure 4. When th drilling shafti'sgiv'en a rotation in the direction indicated by the arrow of Figure 1, the bit will be properly attached to the shaft and ready for operation. The retrieving ring may then be removed from the bit body or raised up the drilling shaft by proper manipulation of the cables.

Being aware o f the possibility of modification in the particular drilling bit construction disclosed without departingfr'omthe fundamental principles of my invention, I do not intend that its scope belimited except as set forth by the appended claims.

1. In drillingapparatus, a rotary drilling shaft, a driiiiiig bitboiy toying a shaft rebeiyiiigbore for permitting tliebit to be slid on the shaft and 'attachedand i'eniovedfrom the l'ower endof seid shaft without removing the shaft from the noie being driiied, means for attaching and detaonirig the booty to trie 1ovver end of the shaft, e cutter, means for mounting the cutter 'o'ri the bit body for movement to anop'erative position where it will utthebottoni of the hole being drilled below thejshaft, end means earned by the 'shaft for engaging a rear portion of the cutter within the bore when thebouy is' attached .to the shaft and the outteris in its operative position..

2- .In a. drilling. eppaffiiu'sif, a ,roiay 'dllihg shatt, a oriiiinjg bit bodyhavin'g 'a shaft 'receivingbore for permitting the bit to, be slid on the shaft one ette-cned and reii'1 "'ti from tri i'ovve'r enti thereoriiieaiis for attac "g 'and dething the body to the. iotvei etici fof 'tbe shaft, a cette; carried by the' body .'aidibvabi into the bore to a position to 'out th' bottom of the hole beneath the end of the shaft, and means forsupporting the portion of the cutter within the bore comprising an abutment on the shaft engageable by a rear portion of the cutter when the bit body is attached to the shaft.

3. In a drilling apparatus, a rotary drilling shaft, a drilling bit having a body provided with a bore for receiving the shaft to thereby permit the bit to be slid over the shaft while said shaft remains in the hole being drilled, means for attaching the bit body to and detaching it from the shaft by a relative rotary movement therebetween, a cutter carried by the bit body and capable of movement into the bore to assume a position for cutting the bottom of the hole beneath the shaft, and means providing an abutment means on the shaft engageable with the cutter to which cutting loads acting laterally on the cutter can be transferred, said abutment means and the portion of the cutter within the bore having engaging relationship when the bit body and shaft have relative movement to bring about the attachment.

4. In a drill-ing apparatus, a rotary drilling shaft, a drilling bit having a body arranged to be moved up and down the shaft while the shaft remains in the hole being drilled, means for attaching and detaching the body to the lower end of the shaft, a cutter pivotally mounted on the body and capable of assuming an inoperative position permitting the bodyy to be moved up and down on the shaft and an operative position by a pivotal movement relative to the body so as to be in a position to cut the bottom of the hole below the shaft, and co--engageable means on the cutter and the shaft for positively moving the cutter to operative position.

5. In a rotary drilling apparatus, a rotary drill shaft, a drilling bit having a body arranged to be moved up and down the shaft While the shaft remains in the hole being drilled, means for attaching and detaching the body to the lower end of the shaft, a cutter pivotally mounted on the body and capable of assumingv an inoperative position permitting the body to be moved up and down on the shaft and an operative position to project laterally from the body by a pivotal movement relative to the body so as to be in a position to cut the bottom of the hole below the shaft, co-engageable means on the cutter and the shaft for moving the cutter, and means on the shaft cooperating with a rear part of theprojecting portion of the cutter and providing backing support therefor.

6. In a rotary drilling apparatus, a rotary drill shaft, a drilling bit having a body provided with a bore for receiving the shaft to thereby permit the bit to be slid over the shaft while said shaft remains in the hole being drilled, means for attaching and detaching the bit body to the lower end of the shaft, a cutter carried by the body and mounted for movement in a single plane into the bore, co-engageable means carried by the cutter and the shaft for moving the cutter into ie bore when the body assumes a position at the lower end of the shaft, and abutment means carried by the shaft and engageable with a rear part of the portion of the cutter within the bore to aid in taking the cutting load acting laterally on the cutter when the bit is attached to the `shaft.

7 In a rotary drilling apparatus, a rotary drill shaft, a drilling bit body, means associated with the end of the drill shaft and with the bit body for attaching said body to the lower end of the shaft so as to be rotated therewith and while the lower end of the shaft remains in the lower part ofthe hole being drilled and for so detaching the body that it will be .free to be moved relatively axially of the shaft to the top of thehole, a cutter pivotally mounted on the body to swing inwardly into the bore in a single plane, and means engageable by a part of the shaft for positively rotating the cutter to a position to operate on the bottom of the hole below the shaft when the body is attached to the shaft and for maintaining said cutter in such position.

- 8. In a drilling apparatus, a rotary drilling shaft, a drilling bit body having a shaft receiving bore for permitting the bit to be slid on the shaft and attached to and removed from the lower end thereof, means for attaching and detaching the body to the lower end of the shaft, a blade type of cutter pivoted to the body and movable in a single plane into the bore to a position to cut the bottom of the hole beneath the end of the shaft, and means for supporting a rear part of I the portion of the cutter within the bore comprising an abutment on the shaft for engagement by the cutter when the bit body is attached to the shaft.

9. In a drilling apparatus, a drill shaft, a drilling bit having a body arranged to be slid up and down the shaft while the shaft remains in the hole being drilled, the lower end of the shaft being provided with shoulder means, means for attaching the bitbody to and detaching it from the lower end of the shaft, a cutter pivotally mounted in the body for movement inwardly in a single plane to assume a position to out the bottom of the hole below the shaft, and means on the cutter for engaging with the said shoulder means for causing the pivoting of the cutter to its cutting position.

10. In a drilling apparatus, a drill shaft, a drilling bit having a body provided with a bore for receiving the shaft to thereby permit the bit to be slid over the shaft while the shaft remains in the hole being drilled and also provided with a cutter receiving slot extending in a general radial direction, the lower end of the shaft being provided with shoulder means for holding the body on the shaft and a recess below the shoulder means, means for attaching the bit body to and detaching it from the lower end of the shaft by a relative rotary movement between the body and shaft, and a cutter mounted in the body slot for move-r ment into the body bore and the shaft recess to thereby assume a position to cut the bottom of the hole below the shaft when the bit is lowered to an attaching position, said shaft recess being of such size and so related to the cutter that the attaching relative rotary movement is not interfered with and upon completion of said attaching movement the cutter will be engaged on its rear side by a side wall of the said recess.

1l. In a drilling apparatus, a rotary drilling shaft, a drilling bit having a body provided with a bore for receiving the shaft to thereby permit the bit to be slid over the shaft while said shaft remains in the hole being drilled and also provided with a longitudinally extending cutter receiving slot, the lower end of the shaft being provided with shoulder means, means for attaching the bit body to and detaching it from the lower end of the' shaft, and a cutter positioned in the slot and pivoted to the body, said cutter being provided with a projection extending into the bore for engagement by the shaft shoulder means as the bit is lowered to an attaching position to thereby cause a rotation of the cutter on its pivot and to a position where it projects into the bore of the ing it from the lower end of the shaft, a cutter positioned in the slot and pivoted to the body, said cutter being provided with a projection extending into the bore for engagement by the shaft shoulder means as the bit is lowered to an attaching position to thereby cause a rotation of the cutter on its pivot and to a position where it projects into the bore of the body and is capable of cutting the bottom surface of the hole below the shaft, and means comprising abutment means on the shaft for engagement by a rear part of the portion of the cutter within the bore and to which lateral cutting loads on the cutter can be transferred when the bit is attached to the shaft.

13. In a drilling apparatus, a drill shaft, a drilling bit having a body provided with a bore for receiving the shaft to thereby permit the bit toI be slid over the shaft while the shaft remains in the hole being drilled and also provided with a cutter receiving slot, the lower end of the shaft being provided with shoulder means and a recess below the shoulder means, means for attaching the bit body to and detaching it from the lower end of the shaft by a relative rotary movement between thebody and shaft, and a blade type cutter positioned in the body slot and pivotally mounted to the body, said cutter being provided with a projection extending into the bore for engagement by the shaft shoulder means as the bit is lowered to an attaching position to thereby swing the cutter into the bore and the shaft recess where it is capable of cutting the bottom surface of the hole below the shaft, said shaft recess being of such size and so related to the cutter that the attaching relative rotary movement is not interfered with and upon completion of said attaching movement the cutter will be engaged on its rear side by a side wall of the recess.

14.. In rotary drilling apparatus, a rotary drill shaft, a drilling bit having a body provided with a shaft receiving bore and arranged to be moved up and down the shaft while the shaft remains inthe hole being drilled, means for attaching and detaching the body to the lower end of the shaft, azcutter member pivotally mounted on the body for inward swinging movement into an operative position in a portion of the bore to thereby cut the hole below the drill shaft, the pivotal axis of said cutter being in a plane at a right angle to the plane in which the axis of the bit body lies, and means for positively preventing swinging movement of the cutter member relative to thev body when the body is attached to the drill shaft.

15. In a rotary drilling apparatus, a rotary drill shaft, ak drilling bit having a body provided with a shaft receiving bore and arranged to be moved up and down the shaft while the shaft remains 8 in the. hole being drilled, means for attaching and detaching the body to the lower end of the shaft, a cutter member pivotally mounted on the body for inward swinging movement in a single plane into an operative position in a portion of the bore, and cooperating means associated with the cutter member and the shaft for positively preventing swinging of the cutter member from its operative position when the bit body is attached to the shaft and notwithstanding any unitary movement of the shaft and bit body in the axial direction of the shaft.

16. In a rotary drilling apparatus, a rotary drill shaft, a drilling bit having a body provided with a shaft receiving bore and arranged to be moved up and down the shaft while the shaft remains in the hole being drilled, means for attaching and `cietaching the body to the lower end of the shaft, a cutter member pivotally mounted on the body for inward swinging movement in a single plane into an operative position in a portion of the bore and co-engageable means on the shaft and the cutter for positively causing said movement by a relative longitudina1 movement between the shaft and body.

1'7. A pivoted cutter for mounting on a removable drilling bit body having a slot and for cooperation with a drilling stern provided with shoulder means, said cutter comprising a iiat body portion for reception in the slot and having a pivot pin receiving opening at its upper end whereby the body portion can be mounted to have pivotal swinging in the slot, said cutter also being provided with shoulder` means at its upper end adjacent its inner edge for engagement with the lstem shoulder means to thereby cause swingingof the cutter inwardly.

18. A'pivoted cutter for mounting on a removable drilling bit body having a slot and for cooperation with a drilling stem provided with shoulder means and a beveled surface, said cutter comprising a flat body portion for reception in the slot and having a pivot pin receiving opening at its upper end whereby the body portion can be mounted to have pivotal swinging in the slot, said cutter also being provided with shoulder means at its upper end adjacent its inner edge for engagement with the stem shoulder means to thereby cause swinging of the cutter inwardly, and with such an inner edge surface as to fully engage the said beveled surface when the cutter moves inwardly.

CARL C. KOELN.

REFERENCES CITED The following references are of record in the iile of this patent:

UNITED STATES PATENTS Number Name Date Re. 22,690 Koeln Nov. 6, 1945 1,470,316 Baldwin Oct. 9, 1923 1,752,092 Kapeluchnikoi Mar. 25, 1930 1,835,108 Arthur et al Dec. 8, 1931 1,858,926 Grau et al. May 17, 1932 FOREIGN PATENTS Number Country Date 173,606 Germany 1906 

